Integrated heat spreader package for heat transfer and for bond line thickness control and process of making

ABSTRACT

A system includes a thermal interface material (TIM) to transfer heat from a die to a heat spreader. The system includes a heat transfer subsystem disposed on the backside surface of the die. In one embodiment, the heat transfer subsystem comprises a first heat transfer material and a second heat transfer material discretely disposed within the first heat transfer material. A method of bonding a die to a heat spreader uses a die-referenced process as opposed to a substrate-referenced process.

This application is a divisional of U.S. patent application Ser. No.10/266996, filed on Oct. 8, 2002, which is incorporated herein byreference.

BACKGROUND INFORMATION

1. Technical Field

Embodiments of the present invention relate to an integrated heatspreader as it is bonded to a die. The bond includes a high-temperaturebump or other structure that is discretely intermingled with alower-temperature material.

2. Description of Related Art

One of the issues encountered when using an integrated heat spreader(IHS) is getting a balance between sufficient adhesion to the die, and ahigh enough heat flow to meet the cooling load of the die. To deal withthis issue, different bonding materials have been tried with varyingresults. If the adhesion is insufficient, the IHS may spall off from thethermal interface material (TIM) and result in a yield issue or a fieldfailure. Another issue encountered is achieving an acceptable IHSstandoff from the die and the board to which the board is mounted.Because of various existing processes, a substrate-referenced process isused that may cause a significant variation in bond-line thickness (BLT)between the top of the die and the bonding surface of the IHS.

TIM BLT is maintained for mechanical reliability of the thermalinterface during thermal cycling. Due to the difference in thecoefficients of thermal expansion of the IHS and the die, there is alarge amount of shear stress imposed on the TIM. Thicker bond linesassist the TIM to withstand these high stresses without failing.

TIM BLT is also an element in the thermal resistance of the thermalinterface. A thinner TIM BLT can result in a lower thermal resistance.Due to these limits in TIM BLT, which can be required for acceptablepackage performance, TIM BLT must be tightly controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the manner in which embodiments of the presentinvention are obtained, a more particular description of variousembodiments of the invention briefly described above will be rendered byreference to the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention that are notnecessarily drawn to scale and are not therefore to be considered to belimiting of its scope, the embodiments of the invention will bedescribed and explained with additional specificity and detail throughthe use of the accompanying drawings in which:

FIG. 1 is an elevational cross-section of a package according to anembodiment;

FIG. 2 is a partial cut-away cross-sectional view of the packagingsystem depicted in FIG. 1 taken along the section line 2-2;

FIG. 3 is a cut-away cross-sectional view of a portion of the packagingsystem depicted in FIG. 1 taken along the section line 3-3;

FIG. 4 is a cutaway cross-sectional view of a portion of an elongate,rectangular package according to an embodiment;

FIG. 5 is a cross-sectional view of an interface subsystem according toan embodiment;

FIG. 6 is a cross-sectional view of an interface subsystem according toan embodiment;

FIG. 7 is a cross-sectional view of an interface subsystem according toan embodiment; and

FIG. 8 is a process flow diagram that depicts non-limiting packagingprocess embodiments.

DETAILED DESCRIPTION

One embodiment of the present invention relates to a system thatincludes a thermal interface material (TIM) intermediary between a heatspreader and a die for heat transfer out of the die. One embodimentincludes a method of bonding a die to a heat spreader that uses adie-referenced process as opposed to a substrate-referenced process.

The following description includes terms, such as upper, lower, first,second, etc. that are used for descriptive purposes only and are not tobe construed as limiting. The embodiments of a device or articledescribed herein can be manufactured, used, or shipped in a number ofpositions and orientations. The terms “die” and “processor” generallyrefer to the physical object that is the basic workpiece that istransformed by various process operations into the desired integratedcircuit device. A board is typically a resin-impregnated fiberglassstructure that acts as a mounting substrate for the die. A die isusually singulated from a wafer, and wafers may be made ofsemiconducting, non-semiconducting, or combinations of semiconductingand non-semiconducting materials.

Reference will now be made to the drawings wherein like structures willbe provided with like reference designations. In order to show thestructures of embodiments most clearly, the drawings included herein arediagrammatic representations of inventive articles. Thus, the actualappearance of the fabricated structures, for example in aphotomicrograph, may appear different while still incorporating theessential structures of embodiments. Moreover, the drawings show onlythe structures necessary to understand the embodiments. Additionalstructures known in the art have not been included to maintain theclarity of the drawings.

FIG. 1 is an elevational cross-section of a packaging system 10according to an embodiment. The packaging system 10 includes a die 12with an active surface 14 and a backside surface 16. The die 12 isconnected to a thermal management device. In one embodiment, the thermalmanagement device is integrated heat spreader 18 that is disposed abovethe backside surface 16 of the die 12. An interface subsystem 20, in theform of a TIM, is disposed between a backside surface 16 and theintegrated heat spreader 18. The interface subsystem 20 includes a firstheat transfer material 22 and a second heat transfer material 24 that isdiscretely disposed within the first heat transfer material 22. In oneembodiment, the second heat transfer material 24 has a higher thermalconductivity that the first heat transfer material 22.

In one embodiment where the two heat transfer materials are metals, thesecond heat transfer material 24 has a higher melting point than thefirst heat transfer material 22. In one embodiment where the first heattransfer material is an organic, the second heat transfer material 24has a melting point that is higher than the curing temperature of thefirst heat transfer material 22.

In another embodiment, the first heat transfer material 22 in anorganic-inorganic composite. The organic-inorganic composite in oneembodiment includes a polymer, optionally an inorganic dielectric, andoptionally at least one metallic. The inorganic dielectric may be amaterial as is used as filler in thermal interface structures. Oneembodiment of an inorganic dielectric is fused silica and the like.Where a metallic material is used as a portion of an organic-inorganiccomposite, the metallic material in one embodiment is a lowmelting-point solder or the like.

As depicted in FIG. 1, the interface subsystem 20 is depicted as havinga low melting-point solder first heat transfer material 22 having afirst melting point and a high melting-point solder second heat transfermaterial 24 that is discretely disposed within the first heat transfermaterial 22 and having a second melting point that is higher than thatof the first melting point. In one embodiment, the packaging system 10includes a second heat transfer material 24 that is at least one solderisland that is discretely disposed within the first heat transfermaterial 22.

In one embodiment, a reactive solder system is used. A reactive soldermaterial includes properties that allow for adhesive and/orheat-transfer qualities. For example, the reactive solder material canmelt and resolidify without a pre-flux cleaning that was previouslyrequired. Further, a reactive solder embodiment can also include bondingwithout a metal surface. Without the need of a metal surface forbonding, processing can be simplified.

In one embodiment, a reactive solder includes a base solder that isalloyed with an active element material. In one embodiment, a basesolder is indium. In one embodiment, a base solder is tin. In oneembodiment, a base solder is silver. In one embodiment, a base solder istin-silver. In one embodiment, a base solder is at least onelower-melting-point metal with any of the above base solders. In oneembodiment, a base solder is a combination of at least two of the abovebase solders. Additionally, conventional lower-melting-pointmetals/alloys can be used.

The active element material is alloyed with the base solder. In oneembodiment, the active element material is provided in a range fromabout 2% to about 30% of the total solder. In one embodiment, the activeelement material is provided in a range from about 2% to about 10%. Inone embodiment, the active element material is provided in a range fromabout 0.1% to about 2%.

Various elements can be used as the active element material. In oneembodiment, the active element material is selected from hafnium,cerium, lutetium, other rare earth elements, and combinations thereof.In one embodiment, the active element material is a refractory metalselected from titanium, tantalum, niobium, and combinations thereof. Inone embodiment, the active element material is a transition metalselected from nickel, cobalt, palladium, and combinations thereof. Inone embodiment, the active element material is selected from copper,iron, and combinations thereof. In one embodiment, the active elementmaterial is selected from magnesium, strontium, cadmium, andcombinations thereof.

The active element material when alloyed with the base solder can causethe alloy to become reactive with a semiconductive material such as thebackside surface 16 of the die 12. The alloy can also become reactivewith an oxide layer of a semiconductive material such as silicon oxide,gallium arsenide oxide, and the like. The alloy can also become reactivewith a nitride layer of a semiconductive material such as siliconnitride, silicon oxynitride, gallium arsenide nitride, gallium arsenideoxynitride, and the like.

Reaction of the alloy with the die 12 can be carried out by thermalprocessing. Heat can be applied by conventional processes, such that theactive element materials reach the melting zone of the base solder. Forexample, where the base solder includes indium, heating is carried outin a range from about 150° C. to about 200° C.

During reflow of the alloy, the active element(s) dissolve and migrateto the backside surface 16 of the die 12. Simultaneously, the basesolder bonds to the integrated heat spreader 18. It is not necessarythat the backside surface 16 be metalized prior to soldering. The solderjoint (not depicted) that is formed by the reactive solder material candisplay a bond strength in a range from about 1,000 psi and about 2,000psi.

FIG. 2 is a partial cut-away cross-sectional view of the packagingsystem 10 taken along the section line 2-2′. It is noted that in FIG. 1,the integrated heat spreader 18 is attached to a mounting substrate 26such as a printed circuit board (PCB), such as a main board, amotherboard, a mezzanine board, an expansion card, or another mountingsubstrate, with a bonding material 28 that secures a lip portion 30 ofthe integrated heat spreader 18 thereto. In one embodiment, the thermalmanagement device is a heat sink without a lip structure such as asimple planar heat sink. In one embodiment the thermal management deviceincludes a heat pipe configuration. It is noted in FIG. 1 that the die12 is disposed between the interface subsystem 20 and a series ofelectrical bumps 32 that are in turn each mounted on a series of bondpads 34. The electrical bumps 32 make contact with the active surface 14of the die 12. Contrariwise, the interface subsystem 20 makes thermalcontact with the backside surface 16 of the die 12.

As taken along the section line 2-2′, FIG. 2 illustrates a cross-sectionof the bonding material 28 that fastens a lip portion 30 (FIG. 1) of theintegrated heat spreader 18 (FIG. 1) to the mounting substrate 26 (FIG.1). Additionally, the electrical bumps 32 are depicted in a ball gridarray as is known in the art.

FIG. 3 is a cut-away cross-sectional view of a portion of the packagingsystem 10 depicted in FIG. 1 taken along the section line 3-3′. It canbe seen in FIG. 3, that the lip portion 30 of the integrated heatspreader 18 is exposed in this view. Additionally, FIG. 3 depicts across-section of the interface subsystem 20, which includes a pattern ofsolder islands that are the second heat transfer material 24 and thatare discretely disposed within the first heat transfer material 22.Although the pattern of solder islands in the second heat transfermaterial 24 is depicted as a five-element grouping, patterning accordingto various embodiments includes a single solder island, two solderislands, three solder islands that are either linearly arranged orotherwise, and multiple solder islands that are arrayed according to theneeds of a given application of an embodiment.

According to an embodiment, the heat transfer materials include solder.The solder may contain lead (Pb) or be a substantially Pb-free solder.By “substantially Pb-free solder”, it is meant that the solder is notdesigned with Pb content according to industry trends. A substantiallyPb-free solder in one embodiment includes an SnAgCu solder as is knownin the art.

One example of a Pb-containing solder includes a tin-lead solder. Inselected embodiments, Pb-containing solder is a tin-lead soldercomposition such as from 97% tin (Sn)/3% lead (Sn3Pb). A tin-lead soldercomposition that may be used as the first heat transfer material 22 oras the second heat transfer material 24 is a Sn63Pb composition of 37%tin/63% lead. In any event, the Pb-containing solder may be a tin-leadsolder comprising Sn_(x)Pb_(y), wherein x+y total 1, and wherein x is ina range from about 0.3 to about 0.99. In one embodiment, thePb-containing solder is a tin-lead solder composition of Sn3Pb for thefirst heat transfer material 22, and for the second heat transfermaterial 24, it is a tin-lead solder composition of Sn63Pb.

The following discussion refers specifically to structures depicted inFIGS. 1-3, but it applies generally to embodiments set forth herein. Inone embodiment, the first heat transfer material 22 includes aPb-containing solder, and the second heat transfer material 24 containsa Pb-containing solder that has a higher melting point than the firstheat transfer material 22. In another embodiment, the first heattransfer material 22 includes a Pb-containing solder, and the secondheat transfer material 24 contains a substantially Pb-free solder thathas a higher melting point than the first heat transfer material 22. Inanother embodiment, the first heat transfer material 22 includes asubstantially Pb-free solder, and the second heat transfer material 24also contains a substantially Pb-free solder that has a higher meltingpoint than the first heat transfer material 22. In another embodiment,the first heat transfer material 22 includes a substantially Pb-freesolder, and the second heat transfer material 24 includes aPb-containing solder that has a higher melting point than the first heattransfer material 22.

In one embodiment, the solder islands are arranged in an elongate,rectangular configuration that may follow the outline of a rectangulardie, as will now be discussed with reference to FIG. 4.

FIG. 4 is a cut-away cross-sectional view of a portion of an elongate,rectangular package according to an embodiment. FIG. 4 depicts thepackaging system 110 that would be taken along a section line similar tothe section line 3-3′ from FIG. 1 and is analogous in its view to theview taken in FIG. 3. In this embodiment, an elongate, rectangular dieheat spreader 118 has a symmetry to match an elongate, rectangular die(not pictured). The elongate, rectangular die is bonded to a likewiseelongate, rectangular interface subsystem 120. It is noted that acollection of solder islands, such as depicted in FIG. 3, includessolder islands 124, 124A, and 124B of varying sizes and orientations oflarger and smaller discrete occurrences of the second heat transfermaterial 24. The varying sizes and orientations of larger and smallerdiscrete occurrences of the second heat transfer material 24 aredepicted in FIG. 3 in arbitrary number, shape, size, and location. As isnoted, there are larger solder islands that are selected to be disposedadjacent to a die at the more active regions thereof. By way ofnon-limiting example, a given solder island 124B that is larger isdisposed directly above a more active region of the die 112 (notpictured) such as an array of embedded dynamic random access memory(DRAM), the sense amplifiers thereof, and the like. A more active regionof a die is understood to be, in one embodiment, a region that generatesa greater amount of heat than the average per area heat generation. Byplacing a larger solder island above the die at a more active region, alarger solder island acts as a heat transfer conduit that has a higheroverall heat transfer coefficient than the heat transfer capability of asmaller solder island, or, for that matter, the first heat transfermaterial 122 alone. This larger heat transfer capability represents alowered resistance to heat flow between the heat-generating die and theheat-sinking heat spreader 118. In one embodiment, the heat spreader 118includes a lip portion 130 similar to the embodiment depicted in FIGS. 1and 3.

FIG. 5 is a cross-sectional view of an interface subsystem 220 accordingto an embodiment. The interface subsystem 220 of FIG. 5 is similar tothe interface subsystem 20 that is depicted in FIG. 1. According tovarious embodiments, the interface subsystem 220 is a combination of alow melting-point solder first heat transfer material 222 and a highermelting-point solder second heat transfer material 224. As set forthherein, the two heat transfer materials are selected from a combinationof a Pb-containing solder and a substantially Pb-free solder. In anotherembodiment, the interface subsystem 220 includes an organic first heattransfer material 222 and a metallic second heat transfer material 224.As set forth herein, the first heat transfer material 222 has a firstcure temperature that is lower than the melting point of the second heattransfer material 224. Similar to other embodiments as set forth herein,the placement of second heat transfer material 224 as discreteoccurrences thereof may be located above a more active region of a diein order to expedite heat transfer away from the die.

FIG. 6 is a cross-sectional view of an interface system 320 according toan embodiment. Interface subsystem 320 includes an organic/inorganiccomposite. In one embodiment, the organic/inorganic composite includesan organic matrix 322 and a metal flake 323 along with a second heattransfer material 324. Although the metal flake 323 is depicted in thisembodiment as a flake, the metal may be in other shapes. In oneembodiment, the metal flake 323 is a substantially spherical powder thathas an average diameter in a range from about 0.1 micron to about 10micron. The second heat transfer material 324, which is in oneembodiment a high melting-point solder, is either a Pb-containing solderor a substantially Pb-free solder as set forth herein.

FIG. 7 is a cross-sectional view of an interface subsystem 420 accordingto an embodiment. The interface subsystem 420 includes a metal/nonmetalcomposite in an organic matrix 422. In one embodiment, the organicmatrix 422 includes an organic material that acts as a matrix for aninorganic dielectric material 421 and a metallic material 423. In thisembodiment, the metallic material 423 is depicted as having reflowedunder a thermal load and has at least partially wetted the inorganicdielectric material 421. The combination of the inorganic dielectricmaterial 421 and the metallic material 423 presents a conglomeratechannel from one surface of the interface subsystem 420 to an oppositesurface thereof. As such, heat transfer through the organic matrixmaterial 422 is expedited. Similarly, a high melting-point solder isdepicted in an embodiment as the second heat transfer material 424.

Another embodiment relates to a die system. An embodiment of the diesystem is depicted in some of the structures illustrated in FIG. 1 byway of non-limiting example. With reference to FIG. 1, in oneembodiment, the die system includes the die 12 and the interfacesubsystem 20 as set forth herein according to the various embodiments.Further, the die system in one embodiment includes the interfacesubsystem 20 that is the first heat transfer material 22 alone. Inanother embodiment, the die system includes the interface subsystem 20with the first heat transfer material 22 and the second heat transfermaterial 24 disposed in the first heat transfer material 22. In anotherembodiment, the die system includes the second heat transfer material 24alone that has a discrete patterning upon the die backside surface 16.The discrete patterning of the second heat transfer material 24 alone,upon the die backside surface 16, is a subset embodiment of thepackaging system 10, as depicted in FIG. 1, wherein the discretepatterning upon the die 12 may be produced by a distinct businessentity. For example, the heat spreader may be produced by a firstcompany or division within a company, and the die with discretepatterning may be produced by a second company or division.

The die system in another embodiment includes the mounting substrate 26disposed below the die 12. In other words, the die 12, the electricalbumps 32, and their bond pads 34 as mounted upon the mounting substrate26, represent a package precursor according to this embodiment. Inanother embodiment, the die system includes the mounting substrate 26and other structures as set forth herein and the integrated heatspreader 18 disposed above the die 12. As depicted in FIG. 1, theinterface subsystem 20 is disposed between to the die 12 and theintegrated heat spreader 18.

Another embodiment relates to a thermal interface alone as depicted inFIG. 1 (interface subsystem 20), FIG. 5 (interface subsystem 220), FIG.6 (interface subsystem 320), and FIG. 7 (interface subsystem 420).According to an embodiment, the high melting-point solder second heattransfer material 24 (FIG. 1, for example) has at least one solderisland that has a characteristic thickness that is in a range from about0.1 micron to about 25 micron. The characteristic thickness is selectedto achieve a preferred bond line thickness (BLT) as is understood in theart. Referring to FIG. 1, the BLT 36 in this embodiment closely tracksthe solder island characteristic thickness, and it is larger than thesolder island characteristic thickness. In other words, the BLT 36 hassubstantially the same thickness as the interface subsystem 20. In oneembodiment, the BLT 36 is in a range from about 1 mil to about 25 mils.In one embodiment, the BLT 36 is in a range from about 2 mils to about10 mils. In another embodiment, the BLT 36 is in a range from about 10mils to about 20 mils. In one embodiment, the BLT 36 of a polymermatrix-containing material is less than the BLT 36 of a metalmatrix-containing material.

In another embodiment, the high melting-point solder second heattransfer material 24 (FIG. 1, for example) is present in relation to thefirst heat transfer material 22 in a volume range from about 0.1% toabout 5%. In another embodiment, the high melting-point solder secondheat transfer material 24 is present in relation to the first heattransfer material 22 in a volume range from about 0% to about 0.1 %. Inanother embodiment, the high melting-point solder second heat transfermaterial 24 is present in relation to the first heat transfer material22 in a volume range from about 0% to about 100%. In another embodiment,the high melting-point solder second heat transfer material 24 ispresent in relation to the first heat transfer material 22 in a volumerange from about 2% to about 10%.

Another embodiment relates to packaging process embodiments 800 thatincludes bringing an integrated heat spreader and a die into TIMintermediary contact through an interface subsystem to achieve a BLTaccording to embodiments set forth herein.

FIG. 8 is a process flow diagram that depicts non-limiting packagingprocess embodiments. According to the various process flow embodimentsdepicted in FIG. 8, the interface subsystem may be configured partiallyon the integrated heat spreader, partially on the die, entirely on theintegrated heat spreader, or entirely on the die.

At 810, representing a first process flow embodiment, an integrated heatspreader (IHS) is contacted with a first heat transfer material, and thefirst heat transfer material is contacted with a die. The double-headedarrows in FIG. 8 indicate that the process flow may be in eitherdirection. In other words, the first heat transfer material in oneembodiment is disposed first against the integrated heat spreader,followed by disposition of the first heat transfer material against thedie. Alternatively, the first heat transfer material in one embodimentis disposed first against the die, followed by disposition of the firstheat transfer material against the integrated heat spreader.

At 820, representing a second process flow embodiment, an integratedheat spreader is contacted with a first heat transfer material. Thefirst heat transfer material is contacted with a second heat transfermaterial that is disposed on a die. The double-headed arrows indicatealternative process flows as set forth above.

At 830, representing a third process flow embodiment, an integrated heatspreader is contacted with a second heat transfer material. The secondheat transfer material is contacted with a first heat transfer materialthat is disposed on a die. The double-headed arrows indicate alternativeprocess flows as set forth above.

At 840, representing a fourth process flow embodiment, an integratedheat spreader is contacted with combined first and second heat transfermaterials. The combined first and second heat transfer materials arecontacted with a die. The double-headed arrows indicate alternativeprocess flows as set forth above. In another embodiment, the order ofplacing the first and second heat transfer materials onto the IHS isreversed.

At 850, representing a fifth process flow embodiment, a die is contactedwith combined first and second heat transfer materials. The combinedfirst and second heat transfer materials are contacted with a die. Thedouble-headed arrows indicate alternative process flows as set forthabove. In another embodiment, the order of placing the first and secondheat transfer materials onto the die is reversed.

As depicted in the various process flow embodiments depicted in FIG. 8,it is noted that the die 12 (FIG. 1) is previously disposed upon amounting substrate 26 (also FIG. 1). Further as depicted in FIG. 1, itis noted that an integrated heat spreader clip 38 is used to impart apressure to the die-interface-heat spreader at least partially through aspring 40. Depending upon the combination of interface subsystem 20 andother factors such as adhesive gelling time, organic curing time, lowmelting-point reflow time, and others, the exact tension of the spring40 is selected to the requirements of a given packaging system.

According to an embodiment, the bonding process of bringing anintegrated heat spreader and a die into intermediary contact through aninterface subsystem 20, 120, 220, 320, or 420 is referred to as adie-referenced process. The die-referenced process relates to thesituation that the die 12 is already affixed upon the mounting substrate26. And as in some embodiments, a second heat transfer material 24 isdisposed between the integrated heat spreader 18 and the backsidesurface 16 of the die 12 while tensing the system with the spring 40.Accordingly, the variability in bonding thickness may often largely bein the bonding material 28 as it bridges the space between the lip 30 ofthe integrated heat spreader 18 and the mounting substrate 26.

In a general embodiment, after bringing the integrated heat spreaderinto intermediary contact with the die through the interface subsystemaccording to various embodiments, bonding the interface subsystemincludes reflowing the low melting-point solder first heat transfermaterial, and/or curing an organic first heat transfer material.Additionally, where a second heat transfer material is disposed in afirst heat transfer material, the solder reflowing process is carriedout after bringing the structures together. Where the first heattransfer material is an organic material, a curing and/or hardeningprocess is carried out after bringing the structures together. Where thefirst heat transfer material is an organic/inorganic composite, curing,hardening, and/or reflowing is carried out after bringing the structurestogether.

It is emphasized that the Abstract is provided to comply with 37 C.F.R.§ 1.72(b) requiring an Abstract that will allow the reader to quicklyascertain the nature and gist of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims.

In the foregoing Detailed Description, various features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments of the inventionrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive subject matter lies in lessthan all features of a single disclosed embodiment. Thus the followingclaims are hereby incorporated into the Detailed Description ofEmbodiments of the Invention, with each claim standing on its own as aseparate preferred embodiment.

It will be readily understood to those skilled in the art that variousother changes in the details, material, and arrangements of the partsand method stages which have been described and illustrated in order toexplain the nature of this invention may be made without departing fromthe principles and scope of the invention as expressed in the subjoinedclaims.

1-9. (canceled)
 10. An integrated heat spreader system comprising: aheat spreader body having a recess; an interface subsystem in therecess, wherein the interface subsystem is selected from (1) a firstheat transfer material, (2) the first heat transfer material and asecond heat transfer material discretely disposed within the first heattransfer material, and (3) the second heat transfer material alonehaving a discrete patterning within the recess. 11-13. (canceled) 14.The integrated heat spreader system according to claim 10, wherein thefirst heat transfer material includes an organic-inorganic composite.15. The integrated heat spreader system according to claim 10, whereinthe first heat transfer material further includes: an organic-inorganiccomposite including a polymer or a resin; optionally an inorganicdielectric; and optionally at least one metallic. 16-18. (canceled) 19.A thermal interface comprising: a first heat transfer material, selectedfrom a low melting point solder, a polymer, a polymer and a low meltingpoint solder, a polymer and an inorganic dielectric, and a polymer and alow melting-point solder and an inorganic dielectric; and a highmelting-point solder second heat transfer material, discretely disposedwithin the first heat transfer material, wherein the high melting-pointsolder second heat transfer material has a higher thermal conductivitythan the first heat transfer material.
 20. The thermal interfaceaccording to claim 19, wherein the high melting point solder second heattransfer material includes at least one solder island that has acharacteristic thickness in a range from about 0.1 micron to about 25micron.
 21. (canceled)
 22. The thermal interface according to claim 19,further including: an integrated heat spreader, wherein the thermalinterface is on the integrated heat spreader.
 23. (canceled)
 24. Thethermal interface according to claim 19, wherein the first heat transfermaterial is a low melting point solder, and the high melting-pointsolder second heat transfer material is present in a volume range fromabout 0% to about 5%.
 25. A packaging process comprising: coupling athermal management device to a die through an interface subsystem,wherein the thermal management device is selected from an integratedheat spreader, a heat pipe, and a planar heat sink, and wherein theinterface subsystem is selected from a first heat transfer material, andthe first heat transfer material and a second heat transfer materialdiscretely disposed within the first heat transfer material, wherein thefirst heat transfer material has either a first melting temperature or afirst curing temperature, and the second heat transfer material has asecond melting temperature higher than the first temperature; andbonding the interface subsystem to the thermal management device and thedie.
 26. The process according to claim 25, wherein the first heattransfer material is selected from a low melting-point solder, anorganic composition, and a combination thereof, and wherein bonding theinterface subsystem includes reflowing the low melting-point solder orcuring and hardening the organic composition.
 27. The process accordingto claim 25, wherein the first heat transfer material includes a lowmelting-point solder, wherein the second heat transfer material includesa high melting-point solder, and wherein bonding the interface subsystemincludes reflowing the low melting-point solder.
 28. The processaccording to claim 25, wherein coupling the thermal management device tothe die through an interface subsystem further includes: disposing thefirst heat transfer material against the thermal management device;disposing the second heat transfer material against the die; andcoupling the first heat transfer material and the second heat transfermaterial.
 29. The process according to claim 25, wherein coupling thethermal management device to the die through an interface subsystemfurther includes: disposing the first heat transfer material and thesecond heat transfer material against the thermal management device; andcoupling the first heat transfer material and the second heat transfermaterial with the die.
 30. The process according to claim 25, whereincoupling the thermal management device to the die through an interfacesubsystem further includes: disposing the first heat transfer materialand the second heat transfer material against the die; and coupling thefirst heat transfer material and the second heat transfer material withthe thermal management device.